libsecret: Don't use non-portable sed -i shell command

https://bugzilla.gnome.org/show_bug.cgi?id=720087
test-attributes: Remove deprecated use of g_test_trap_fork()
configure: Bump glib version

And cleanup how we list our version dependencies, required and optional
configure: No need for GTK or GTK compile flags
tests: Stop when either the javascript or python tests fail
tests: Fix up the javascript and python tests
secret-prompt: Use string window ids

This is more portable and exposes what's actually in the Secret
Service API. This change was made before going stable with the
prompting functions.
Mark most of unstable API as stable

This is with the exception of the 'path' functions.
Bump version number